The Steam Engine and Gas and Oil Engines: A Book for the Use of Students who Have Time to Make Experiments and CalculationsMacMillan, 1899 - 646 páginas |
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adiabatic Answer assume atmospheric average back pressure boiler calculate carbon Carnot cycle cent Centigrade coal combustion compression condensing engine connecting rod constant crank pin crank shaft cubic feet cubic foot curve cylinder dead point diameter distance draw eccentric efficiency electrical entropy evaporation EXERCISE exhaust expansion Fahrenheit flues fluid foot-pounds force friction fuel gas engine gases gear give half travel heat units Hence horizontal horse-power hour ignition indicated horse-power indicator diagram jacket latent heat load main crank metal motion non-condensing engine numbers octave p₁ pipe piston plate position pound of steam pump Rankine cycle represents revolutions per minute simple harmonic motion slide specific heat speed square foot square inch steam engine stroke student stuff surface surface condenser t₁ tubes usually valve velocity vertical volume weight Willans
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Página 527 - ... delivery was measured by observing the indications of a water-meter, and correcting the readings as already described, meter-readings being taken at frequent intervals, and each experiment being continued for a sufficient length of time to obtain a number of duplicate readings for equal intervals. The pressures in column 8 were obtained by throttling the steam supplied to the injector, and observing the pressure at which it ceased to work, each experiment being repeated several times with precisely...
Página 515 - ... cannot have a much higher temperature in the one case than in the other. That it should be somewhat higher is strictly in accordance with the theory as stated above. It must, however, be noticed that the foregoing conclusion is based on the assumption that the surface of the tube is kept at the same constant temperature, a condition which it is easy to see can hardly be fulfilled in practice. The method by which this is usually attempted is by surrounding the tube on the outside with some fluid...
Página 515 - ... be constant but will diminish with the quantity of heat carried off by the air. It may be imagined that the difference will not be great : a variety of experiments lead me to suppose that it is much greater than is generally supposed. It is obvious that if the previous conclusions be correct this difference would be diminished by keeping the water in motion, and the more rapid the motion the less would be the difference. Taking these things into consideration the following experiments may, I...
Página 515 - ... temperature as the tube. 2. As the velocity increased the temperature at which the gas would emerge would gradually diminish, rapidly at first, but in a decreasing ratio until it would become sensibly constant and independent of the velocity. The velocity after which the temperature of the emerging gas would be sensibly constant can only be found for each particular gas by experiment ; but it would seem reasonable to suppose that it would be the same as that at which the resistance offered by...
Página 515 - ... to as little as 6, but whatever the proportions may be each engine furnishes a means of comparing the efficiency of the tubes for high and low velocities of the air through them. It has been a matter of surprise how completely the steam-producing power of a boiler appears to rise with the strength of blast or the work required from it. And as the boilers are as economical when working with a high blast as with a low, the air going up the chimney cannot have a much higher temperature in the one...
Página 515 - ... must, however, be noticed that the foregoing conclusion is based on the assumption that the surface of the tube is kept at the same constant temperature, a condition which it is easy to see can hardly be fulfilled in practice. The method by which this is usually attempted is by surrounding the tube on the outside with some fluid the temperature of which is kept constant by some natural means, such as boiling or freezing, for instance the tube is surrounded with boiling water. Now although it...
Página 515 - ... at its two surfaces. Hence if air be forced through a tube surrounded with boiling water, the temperature of the inner surface of the tube will not be constant, but will diminish with the quantity of heat carried off by the air. It may be imagined that the difference will not be great : a variety of experiments lead me to suppose that it is much greater than is generally supposed. It is obvious that, if the previous conclusions be correct, this difference would be diminished by keeping the water...
Página 527 - ... water-supply was perfect for all positions of the starting-lever, within the capacity of the instrument. " Table I. shows the results of the experiments on delivery of injector, temperature of delivered water, and other particulars, which are fully detailed in the general heading and in the several columns. For each pressure of steam noted in column 1, the water was delivered by the injector into the boiler under approximately the same pressure. The delivery was measured by observing the indications...